50 research outputs found
First record of Chrysopelea taprobanica Smith, 1943 (Squamata: Colubridae) from India
Chrysopelea taprobanica Smith, 1943 was previously
considered to be endemic to the dry and intermediate zones
of Sri Lanka. However, an adult specimen of C. taprobanica
was collected from Seshachalam Biosphere Reserve of Andhra
Pradesh, India, being the first record of this snake species
from India, significantly extending the known range of distribution
of the species. The dry zones of peninsular India were
connected with Sri Lanka as recently as ca. 17,000 years ago,
which probably allowed movement of species between these
two regions
Amphibians and Reptiles Diversity in Bukit Baka Bukit Raya National Park, West Kalimantan
Studies related to herpetofauna diversity in the Bukit Baka Bukit Raya National Park (Tanakaya), West Kalimantan are very limited. Data related to the richness of amphibians and reptiles in this area are important for the management of the area in the future. We conducted amphibian and reptile surveys in Tanakaya in July-August 2019 using Visual Encounter Survey methods at five sites (Belaban Resort: Km 37 & 39; Resort Rantau Malam: Batu Lintang, Sungai Mangan, and Hulu Rabang). We recorded 50 amphibian species from nine families and 25 reptile species from seven different families. Twenty of these species are new records for Tanakaya. The highest diversity (H' = 2.94) was found in Batu Lintang, while the highest evenness (E = 0.55) was in Sungai Mangan, and the highest community similarity index (IS = 0.6) was in Batu Lintang with Km 37. Combined with previous studies, there have been 142 species (78 species of amphibians and 64 species of reptiles) recorded from Tanakaya. Further study is needed to fully understand the herpetofauna in Tanakaya, but our data highlights the importance of the national park for preserving global biodiversity
Advanced survey effort required to obtain bat assemblage data in temperate woodlands (Chiroptera)
There is a lack of precise guidelines concerning the survey effort required for advanced bat surveys in temperate European woodlands, resulting in a lack of standardisation in survey methods. In this study we assess catch data from 56 bat trapping surveys at 11 UK woodland sites in order to provide recommendations for mist net survey effort required to gain meaningful bat assemblage data in temperate woodlands. Species accumulation curves were produced and were used to develop two novel values for survey effort: the minimum survey threshold (MST), whereby surveyors are more likely than not to encounter less dominant species; and the known species threshold (KST), the point where a given percentage (in our case, 75%) of the known species assemblage for a site is likely to be reached and beyond which there are diminishing returns for survey effort. For our data, the mean of MST was 17.4 net hours, and for KST, the mean was 29.8 net hours. The MST and KST values were reached during the second and third surveys, respectively. These proposed values are adaptable based on location and known species assemblage and may be used for planning advanced bat surveys in temperate woodlands not only to maximise survey efficacy and use of limited resources but to ensure ethical viability of undertaking advanced surveys in the first place.Published onlin
Rediscovery of the Endangered Carchi Andean Toad, \u3cem\u3eRhaebo colomai\u3c/em\u3e (Hoogmoed, 1985), in Ecuador, with Comments on Its Conservation Status and Extinction Risk
Since 1984 there have been no records of Rhaebo colomai (Hoogmoed, 1985) within the territory of Ecuador. This species was known from 2 localities in the province of Carchi, northwestern Ecuador, and the department of Nariño, southwestern Colombia, which were reported in 1979 and 2015, respectively. We report the recent sightings of R. colomai at 3 new localities in Ecuador and discuss and evaluate this species’ extinction risk and conservation status
Endemic, endangered, and evolutionarily significant: Cryptic lineages in Seychelles’ frogs
Cryptic diversity that corresponds with island origin has been previously reported in the endemic, geographically restricted sooglossid frogs of the Seychelles archipelago. The evolutionary pattern has not been fully explored, and given current amphibian declines and the increased extinction risk faced by island species, we sought to identify evolutionarily significant units (ESUs) to address conservation concerns for these highly threatened anurans. We obtained genetic data for two mitochondrial (mtDNA) and four nuclear (nuDNA) genes from all known populations of sooglossid frog (the islands of Mahé, Praslin, and Silhouette) to perform phylogenetic analyses and construct nuDNA haplotype networks. Bayesian and maximum likelihood analyses of mtDNA support monophyly and molecular differentiation of populations in all species that occur on multiple islands. Haplotype networks using statistical parsimony revealed multiple high-frequency haplotypes shared between islands and taxa, in addition to numerous geographically distinct (island-specific) haplotypes for each species. We consider each island-specific population of sooglossid frog as an ESU and advise conservation managers to do likewise. Furthermore, our results identify each island lineage as a candidate species, evidence for which is supported by Bayesian Poisson Tree Processes analyses of mtDNA, and independent analyses of mtDNA and nuDNA using the multispecies coalescent. Our findings add to the growing understanding of the biogeography and hidden diversity within this globally important region
Microsatellite discovery in an insular amphibian (Grandisonia alternans) with comments on cross-species utility and the accuracy of locus identification from unassembled Illumina data
The Seychelles archipelago is unique among isolated oceanic islands because it features an endemic radiation of caecilian amphibians (Gymnophiona). In order to develop population genetics resources for this system, we identified microsatellite loci using unassembled Illumina MiSeq data generated from a genomic library of Grandisonia alternans, a species that occurs on multiple islands in the archipelago. Applying a recently described method (PALFINDER) we identified 8001 microsatellite loci that were potentially informative for population genetics analyses. Of these markers, we screened 60 loci using five individuals, directly sequenced several amplicons to confirm their identity, and then used eight loci to score allele sizes in 64 G. alternans individuals originating from five islands. A number of these individuals were sampled using non-lethal methods, demonstrating the efficacy of non-destructive molecular sampling in amphibian research. Although two loci satisfied our criteria as diploid, neutrally evolving loci with the statistical power to detect population structure, our success in identifying reliable loci was very low. Additionally, we discovered some issues with primer redundancy and differences between Illumina and Sanger sequences that suggest some Illumina-inferred loci are invalid. We investigated cross-species utility for eight loci and found most could be successfully amplified, sequenced and aligned across other species and genera of caecilians from the Seychelles. Thus, our study in part supported the validity of using PALFINDER with unassembled reads for microsatellite discovery within and across species, but importantly identified major limitations to applying this approach to small datasets (ca. 1 million reads) and loci with small tandem repeat sizes
Multi-locus phylogeny and species delimitation of Australo-Papuan blacksnakes (Pseudechis Wagler, 1830: Elapidae: Serpentes)
Genetic analyses of Australasian organisms have resulted in the identification of extensive cryptic diversity across the continent. The venomous elapid snakes are among the best-studied organismal groups in this region, but many knowledge gaps persist: for instance, despite their iconic status, the species-level diversity among Australo-Papuan blacksnakes (Pseudechis) has remained poorly understood due to the existence of a group of cryptic species within the P. australis species complex, collectively termed ‘‘pygmy mulga snakes”. Using two mitochondrial and three nuclear loci we assess species boundaries within the genus using Bayesian species delimitation methods and reconstruct their phylogenetic history using multispecies coalescent approaches. Our analyses support the recognition of 10 species, including all of the currently described pygmy mulga snakes and one undescribed species from the Northern Territory of Australia. Phylogenetic relationships within the genus are broadly consistent with previous work, with the recognition of three major groups, the viviparous red-bellied black snake P. porphyriacus forming the sister species to two clades consisting of ovoviviparous specie
Soft Chemical Control of Superconductivity in Lithium Iron Selenide Hydroxides LiFe(OH)FeSe
Hydrothermal synthesis is described of layered lithium iron selenide hydroxides LiFex(OH)FeSe (x0.2; 0.02 < < 0.15) with a wide range of iron site vacancy concentrations in the iron selenide layers. This iron vacancy concentration is revealed as the only significant compositional variable and as the key parameter controlling the crystal structure and the electronic properties. Single crystal X-ray diffraction, neutron powder diffraction, and X-ray absorption spectroscopy measurements are used to demonstrate that superconductivity at temperatures as high as 40 K is observed in the hydrothermally synthesized samples when the iron vacancy concentration is low ( < 0.05) and when the iron oxidation state is reduced slightly below +2, while samples with a higher vacancy concentration and a correspondingly higher iron oxidation state are not superconducting. The importance of combining a low iron oxidation state with a low vacancy concentration in the iron selenide layers is emphasized by the demonstration that reductive postsynthetic lithiation of the samples turns on superconductivity with critical temperatures exceeding 40 K by displacing iron atoms from the LiFe(OH) reservoir layer to fill vacancies in the selenide layer
The roles of vicariance and isolation by distance in shaping biotic diversification across an ancient archipelago: evidence from a Seychelles caecilian amphibian
© 2020 The Authors. Published by BMC. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1186/s12862-020-01673-wBackground
Island systems offer excellent opportunities for studying the evolutionary histories of species by virtue of their restricted size and easily identifiable barriers to gene flow. However, most studies investigating evolutionary patterns and processes shaping biotic diversification have focused on more recent (emergent) rather than ancient oceanic archipelagos. Here, we focus on the granitic islands of the Seychelles, which are unusual among island systems because they have been isolated for a long time and are home to a monophyletic radiation of caecilian amphibians that has been separated from its extant sister lineage for ca. 65–62 Ma. We selected the most widespread Seychelles caecilian species, Hypogeophis rostratus, to investigate intraspecific morphological and genetic (mitochondrial and nuclear) variation across the archipelago (782 samples from nine islands) to identify patterns and test processes that shaped their evolutionary history within the Seychelles.
Results
Overall a signal of strong geographic structuring with distinct northern- and southern-island clusters were identified across all datasets. We suggest that these distinct groups have been isolated for ca. 1.26 Ma years without subsequent migration between them. Populations from the somewhat geographically isolated island of Frégate showed contrasting relationships to other islands based on genetic and morphological data, clustering alternatively with northern-island (genetic) and southern-island (morphological) populations.
Conclusions
Although variation in H. rostratus across the Seychelles is explained more by isolation-by-distance than by adaptation, the genetic-morphological incongruence for affinities of Frégate H. rostratus might be caused by local adaptation over-riding the signal from their vicariant history. Our findings highlight the need of integrative approaches to investigate fine-scale geographic structuring to uncover underlying diversity and to better understand evolutionary processes on ancient, continental islands.Funding for this research was provided by two grants from the National Science Foundation (BSR 88–17453, BSR 90–24505) [funding for fieldwork and lab work], two grants from the National Geographic Society (Grants 1977: 1633, 1743) [funding for fieldwork], three grants from the University of Michigan Office of the Vice President for Research, and a Research Partnership Award from the University of Michigan to RAN [morphology work]; a joint NHM-UCL IMPACT studentship [to fund STM’s PhD, lab work and fieldwork], Mohamed Bin Zayed Species Conservation Fund [funding for fieldwork] and Systematics Research Fund [funding for fieldwork] to STM; an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under Grant #P20GM103408 to LL [funding for lab work]; a NERC/BBSRC SynTax grant [funding for fieldwork and collaboration], and Darwin Initiative (grant 19–002) [funding for fieldwork, lab work and capacity building] with partners Bristol University, Islands Conservation Society, Seychelles Islands Foundation, Seychelles Ministry of Environment, Seychelles National Parks Authority, Seychelles Natural History Museum, University of Kent, Zoological Society of London to MW, DJG, JJD. The funding bodies played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.Published onlin
Rediscovery of the Endangered Carchi Andean Toad, Rhaebo colomai (Hoogmoed, 1985), in Ecuador, with comments on its conservation status and extinction risk
Since 1984 there have been no records of Rhaebo colomai (Hoogmoed, 1985) within the territory of Ecuador. This species was known from 2 localities in the province of Carchi, northwestern Ecuador, and the department of Nari��o, southwestern Colombia, which were reported in 1979 and 2015, respectively. We report the recent sightings of R. colomai at 3 new localities in Ecuador and discuss and evaluate this species��� extinction risk and conservation status